In this study, diphenyl sulfoxide was prepared by oxidizing diphenyl sulfide with hydrogen peroxide using phosphotungstic acid as catalyst in semi-batch mode. In order to optimize the synthesis process, a four-factor three-level Box-Behnken design was adopted. The result showed that under the optimal condition, namely catalyst concentration 0.19 mmol/mol, oxygen-sulfur ratio 1.08, reaction temperature 30 ºC, and dosing time 15 min, the yield of diphenyl sulfoxide could reach up to 79.05%. In addition, the thermal behavior of synthesis process was systematically investigated using a reaction calorimeter (EasyMax 102) equipped with a situ FTIR monitoring. The receivable mechanism is that H₂O₂ is activated by the catalyst and subsequently reacts with diphenyl sulfide to produce oxidized product. H₂O₂ was relatively stable when PTA was used as catalyst. Thermal risk index was used to assess the thermal hazard of H₂O₂ & PTA. Furthermore, risk matrix method as well as Stoessel criticality diagram was used to assess the thermal risk of the process and an unacceptable risk was obtained. One of the main hidden dangers was the potential chemical splatter caused by decomposition of H₂O₂. It should be equipped with a pre-set quench or sufficient emergency discharge to avoid further loss. The results of this work proposed a solid foundation for the safe operation of this process and can be further used for scale-up.

本研究以磷钨酸为催化剂，采用过氧化氢氧化二苯硫醚，以半间歇方式制备二苯亚砜。为了优化合成过程，采用了四因素三水平 Box-Behnken 设计。结果表明，在催化剂浓度0.19 mmol/mol、氧硫比1.08、反应温度30 ℃、投加时间15 min的最佳条件下，二苯亚砜的收率可达79.05%。此外，使用配备原位 FTIR 监测的反应量热仪(EasyMax 102) 系统地研究了合成过程的热行为。应收机制是H ₂ O ₂被催化剂活化，随后与二苯硫醚反应生成氧化产物。当PTA用作催化剂时，H ₂ O _{2相对稳定。}热风险指数用于评估H ₂ O ₂和PTA的热危害。此外，使用风险矩阵法和斯托塞尔临界图来评估过程的热风险，得到不可接受的风险。主要隐患之一是H ₂ O _{2分解引起的潜在化学飞溅}. 应配备预先设定的骤冷或足够的紧急排放，以避免进一步损失。该工作成果为该工艺的安全运行奠定了坚实的基础，并可进一步用于放大生产。